A build on Ubuntu reported:
|| Generating formatnwfilter.html.tmp
/dados/develop/libvirt/docs/formatnwfilter.html.in|390| HTML parser error : Unexpected end tag : p
|| </p>
|| ^
/dados/develop/libvirt/docs/formatnwfilter.html.in|705| HTML parser error : Unexpected end tag : code
|| <td>End of range of valid source ports</code></td>
|| ^
/dados/develop/libvirt/docs/formatnwfilter.html.in|710| HTML parser error : Unexpected end tag : code
|| <td>Start of range of valid destination ports</code></td>
|| ^
* docs/formatnwfilter.html.in: Fix invalid HTML constructs.
Reported by Eduardo Otubo.